Project Summary/Abstract While antiretroviral therapies are used to successfully manage the course of Human Immunodeficiency Virus (HIV) infection, a cure remains elusive. Current treatments leave patients at a greater risk of renal failure, cardiovascular disease, and cognitive impairments. Furthermore, therapy itself has a number of side effects, but it must be taken indefinitely to prevent the rebound of latent or transcriptionally silent virus. For these reasons, the NIH has prioritized the search for an HIV cure and has particularly emphasized the need for new model systems to analyze latent HIV infection. Most current models use chronically infected cell lines in which the signals that maintain a provirus (integrated virus) in a latent state are interrogated. However, the signals that predispose cells towards harboring a latent provirus during acute infection are unknown. Research into these signals could significantly aid the creation of new therapeutics designed to reduce the size of the latent reservoir. This grant proposes the use of an experimental system in which primary CD4+ T cells are transduced with chimeric antigen receptors (CARs) that mimic endogenous T cell receptors. Because we have a panel of CARs that express different affinities for their ligand, the effects of differential signaling on both viral transcription and the outcome of HIV infection can be contrasted. We hypothesize that the dynamics of T cell receptor signaling at the time of HIV infection determine the transcriptional landscape of the provirus and the potential for latent infection. In Specific Aim 1, luciferase analysis and RT-PCR will be used to test the hypothesis that stronger T cell signaling at the time of infection increases HIV expression in primary cells. In Specific Aim 2, chromatin immunoprecipitation will be used to examine changes in RNA polymerase II processivity and histone acetylation along the HIV genome as a result of differences in signaling at the time of infection. Finally, flow cytometry will be used in Specific Aim 3 to determine if increased T cell signaling during infection decreases the population of cells with inducible latent proviruses. The experiments proposed in this grant will provide mechanistic insights into the establishment of latent infections and may suggest new avenues of approach for preventing the formation of or even eliminating established viral reservoirs.